matlab-readraw

Read RAW camera images from within Matlab, using DCRAW

⚠️ This project has been moved to Gitlab at https://gitlab.com/astrophotography/matlab-readraw This Github repository will then be stalled.

The use of this class boils down to simply creating the object. Then, you may simply use the imread and imfinfo calls as usual, and RAW files will magically be handled.

Example:

In the following example, we just call readraw once, and then all is done with imread and imfinfo as you would do with other image formats.

readraw;
im   = imread('file.RAW');
exif = imfinfo('file.RAW'); 
...
delete(readraw);

NOTES:

NOTE: Each RAW file will be converted to a 16-bits TIFF one at the same location as the initial RAW file. This file is then read again by imread to actually get the image RGB channels. If you have created these files (which are each 146 Mb for 6x4k images), you may either remove them, or further access them without requiring conversion.

Supported RAW camera image formats include:

If you wish to import the RAW files with specific DCRAW options, use the readraw class method 'imread' with options as 3rd argument e.g:

dc = readraw;
im = imread(dc, 'file.RAW', '-a -T -6 -n 100');

and if you wish to get also the output file name and some more information:

[im, info, output] = imread(dc, 'file.RAW', '-T -4 -t 0 -v');

Some useful DCRAW options are:

• -T write a TIFF file, and copy metadata in
• -w -T -6 -q 3 use camera white balance, and best interpolation AHD
• -a -T -6 use auto white balance
• -T -4 use raw data, without color scaling, nor white balance
• -i -v print metadata
• -z set the generated image date to that of the camera
• -n 100 remove noise using wavelets
• -w use white balance from camera or auto
• -t 0 do not flip the image

The default DCRAW setting for the importation is '-T -4 -t 0 -v' to get the raw data.

Methods:

• readraw class instantiation. No argument.
• compile check for DCRAW availability or compile it
• delete remove readraw references in imformats
• imread read a RAW image using DCRAW. Allow more options
• imfinfo read a RAW image metadata using DCRAW

Installation:

Copy the directory and navigate to it. Then type from the Matlab prompt:

addpath('path-to-readraw')
readraw;

READRAW can use any of the following installed tools:

• libraw (with header/include files)
• libraw binary tools (dcraw_emu, raw-identify, simple_dcraw, Win, Linux and MacOSX)
• dcraw (see also Win build, Linux and Win - executable are provided inn this project)
• exiv2 (Win, Linux and MacOSX))
• metacam (Linux only)
• exifprobe (Linux only)

which should be in the executable search path. These can be installed for Debian-like systems (Ubuntu, Mint, Debian...) with:

sudo apt install dcraw libraw-bin exiv2 metacam exifprobe libraw-dev
sudo ln -s /usr/lib/libraw/dcraw_emu /usr/local/bin
sudo ln -s /usr/lib/libraw/raw-identify /usr/local/bin

Packages LibRAW and EXIV2 also exist for Mac OSX. Refer to:

• https://www.exiv2.org/download.html
• https://www.libraw.org/download

and make sure they are in the PATH.

To make use of the libraw direct reader (which is slightly faster than the others), you may have to compile the MeX file for your system by running:

cd path-to-readraw/private
buildMexunpackRaw

which makes use of the excellent contribution from E. Segre. You will need a valid C compiler, supported by Matlab. If this wrapper does not work, use compile(readraw,'dcraw') to use an other RAW reader solution.

If no RAW reader is found, and DCRAW is not yet installed on the computer, you will need a C compiler. The DCRAW C source file (provided with READRAW, private directory) will be built and used, if not there yet.

To force the use of a given RAW reader, use the compile method, e.g.

compile(readraw);               % checks for available readers
compile(readraw, 'compile');    % force compilation of e.g. unpackRaw and DCRAW
compile(readraw, 'dcraw_emu');  % use 'dcraw_emu' as reader

In the last command, it is possible to specify e.g. any of dcraw_emu, dcraw, simple_dcraw, unpackRaw, libraw. for use.

Credits:

• DCRAW is a great tool https://www.cybercom.net/~dcoffin/dcraw/
• Reading RAW files into MATLAB and Displaying Them http://www.rcsumner.net/raw_guide/
• RAW Camera File Reader by Bryan White 2016 https://fr.mathworks.com/matlabcentral/fileexchange/7412-raw-camera-file-reader?focused=6779250&tab=function
• LibRaw MeX https://fr.mathworks.com/matlabcentral/fileexchange/70985-matlab-unpackraw and https://github.com/EastEriq/matlab-unpackRaw

License: (c) E. Farhi, GPL2 (2018). https://gitlab.com/astrophotography/matlab-readraw/